Final Cut Pro X (FCPX) no sound issue

Okay, I have this odd problem. I've recently imported a video clip (that has sound) into Final Cut Pro X (FCPX) - but that clip didn't play any sound when played at its originally imported location (don't know what to call that area of FCPX). Other clips do not exhibit this particular problem. However, the clip with the audio problem will play sound in the timeline if dragged, dropped and subsequently played there.

I made a video clip to better demonstrate the issue I've experienced (only with this one clip).

Final Cut Pro X no sound - YouTube

Final Cut Pro X no sound - YouTube